Introduction: Coronary artery calcium shows a anatomic information and coronary atherosclerotic burde, but myocardial perfusion SPECT shows a physiologic significance of coronary stenosis and stress induced ischemia. Both are valuable in the noninvasive assessment of patients with suspected coronary artery disease. There has been little evaluation regarding the relationship between CAC and adenosine-induced ischemia and how to integrate CAC with myocardial perfusion SPECT. We assessed the relationship between adenosine-induced myocardial ischemia on myocardial perfusion single-photon emission computed tomography (MPS) and magnitude of coronary calcification (CAC) by MDCT in patients undergoing both tests. Subjects and methods: A total of 111 patients underwent adenosine-induced MPS and CAC within 2days. Coronary angiography was done in 55 patients. The frequency of ischemia by MPS was compared to the magnitude of CAC. Results: Among 56 patients with ischemic MPS, the CAC scores were >0 in 87.5%, >100 in 76.8%, and > 400 in 50.0%. Of 25 normal MPS, the CAC scores were >0 in 70.9%, >100 in 34.5%, and > 400 in 14.5%, respectively. Of 38 patient with coronary artery stenosis proved by coronary angiography, the CAC scores were >0 in 92.1%, >100 in 78.9%, and > 400 in 50.0 %, respectively. Of 12 patient without coronary artery stenosis, the CAC scores were >100 in 66.7%, and >400 in 41.7%. Conclusion: Ischemic MPS is associated with a high likelihood of subclinical atherosclerosis by CAC, but it can be also seen for CAC scores <100. The patient without significant coronary artery stenosis, however, may have extensive atherosclerosis by CAC criteria. Although, low CAC scores appear to obviate the need for subsequent testing, but MPS is still needed to diagnosis the myocardial ischemia.